If you don’t have signs of infection like fever, cough with phlegm etc I don’t think you would need to repeat the course of antibiotics.
I would like to know if you have history of seasonal allergy or not? Do you overuse your voice (line singing etc)?
If the answers to above questions are No, then I would consider seeing an ENT specialist if your symptoms have been going on for three weeks now.
Hygiene plays an important role as you mentioned. So try to keep it dry. Avoid underwears which does have good ventilation (contains nylons etc). Use 100% cotton underwear and use a hair drier to dry up after taking shower.